implement post and comment controllers

Wires PostController (recent, show, create, delete, listByUser)
and CommentController (listForPost, create, delete) to the
existing use cases. Posts and comments expose author display
names alongside user IDs. CommentRepository binding added to
RepositoryServiceProvider.

backend/routes/api.php

@@ -1,6 +1,8 @@
 <?php
 
 use App\Controllers\AuthController;
+use App\Controllers\CommentController;
+use App\Controllers\PostController;
 use App\Http\Middleware\AuthMiddleware;
 use Illuminate\Support\Facades\Route;
 
@@ -15,3 +17,32 @@ Route::post('/logout', [AuthController::class, 'logout'])
     ->middleware(AuthMiddleware::class);
 Route::get('/me', [AuthController::class, 'me'])
     ->middleware(AuthMiddleware::class);
+
+Route::get('/posts', [PostController::class, 'recent']);
+Route::get('/posts/{id}', [PostController::class, 'show'])
+    ->whereNumber('id');
+Route::post('/posts', [PostController::class, 'create'])
+    ->middleware(AuthMiddleware::class);
+Route::delete('/posts/{id}', [PostController::class, 'delete'])
+    ->whereNumber('id')
+    ->middleware(AuthMiddleware::class);
+
+Route::get(
+    '/users/{displayName}/posts',
+    [PostController::class, 'listByUser'],
+);
+
+Route::get(
+    '/posts/{postId}/comments',
+    [CommentController::class, 'listForPost'],
+)->whereNumber('postId');
+Route::post(
+    '/posts/{postId}/comments',
+    [CommentController::class, 'create'],
+)->whereNumber('postId')
+    ->middleware(AuthMiddleware::class);
+Route::delete(
+    '/comments/{id}',
+    [CommentController::class, 'delete'],
+)->whereNumber('id')
+    ->middleware(AuthMiddleware::class);